Fireproof girder or beam.



' PATENTED NOV. 3, 1903.

W. N. WIGHT. FIRBPROOF GIRDER 0R BEAM.

APPLICATION FILED JAN. 30, 1903.

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WITNESSES:

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llatented November 3, 1908.

PATnNT4Orrrcn.

VILLIAM N. WIGHT, OF NEW YORK, N. Y.

FIREPROOF GIRDER OR BEAM.

SPECIFICATION 'forming part of Letters Patent No. 742,943, datedNovember 3, 1903.

Application filed January 30,1903. Serial No. 141,098. (No model.)

T0 @ZZ whom it may concern.-

Be it known that I, WILLIAM N. WIGHT, a citizen of vthe United States,residing in the borough of Manhattan,city, county,and State of New York,have invented certain new and useful Improvements in Fireproof Girdersor Beams, of which the following is a specification.

' My invention aims to provide certain improvements in beams or girdersfor use in fireproof buildings which shall be very strong in proportionto their weight, shall be easily constructed, and shall be much betteradapted to resist fire than the steel beams now commonly employed.

My invention provides also improvements in the process of building sucha beam or girder.

My improved-beam may be constructed of concrete and reinforcing metal,such as wirenetting, although certain features of the invention areindependent of the metallic reinforce.

The features of the invention which are separately new are defined inthe claims hereinafter.

Referring to the drawings forming part of this specification andillustrating certain structures in which the invention is embodied,Figure l is a longitudinal section of a beam, taken on the line l 1 ofFig. 2. Fig.

A2 is a central transverse section of the beam shown in Fig. l. Fig. 3is a section similar to Fig. 2, showing the beam in course ofconstruction. Fig.,4 isa longitudinal section of another beam embodyingthe invention, the section being taken on the line 4 ltof Fig. 5. Fig. 5is a central transverse section of the beam shown in Fig. 4. Fig. 6 is asection similar to Fig. 5, showing the beamI in course of construction.Fig. 7 is a section similar to Fig. 5,showing certain additionalfeatures applied thereto. Figs. 8 and 9 are respectively a plan and asection vsimilar to Fig. l of another beam embodying the invention. Fig.10 is a longitudinal section near one of the side edges of another' beamembodying the invention, the plane of section being indicated at lO lO,Fig. 5. Fig.- ll is a side elevation of the beam shown in Fig. 10.

My improved beam as illustrated in its most com plete form includesupper and lower plates or chords of concrete, which are preferablysubstantially horizontal. The upper and lower chords are separated fromeach other a sufficient distance to give the desired depth to the beam,and between them is an arch for transmitting pressures on the upperchord to the lower chord, and preferably end posts for asimilar purpose.Where the arch is made of considerable length-say the entire length ofthe beam-I may provide addi'- tional vertical members'between' the endsof the arch for transmitting downward strains from the upper chord tothe lower. Preferably the concrete is reinforced by a suitablereticulated metal reinforce. Preferably for this purpose I employ a wirenetting or fabric of the generic type of which an example is illustratedin my application for patent, Serial No. 114,868, tiled July 9, 1902,and which may be briefly described as composed of straight wires in onedirection and cross-wires spacing said straight wires and bound theretoat their crossing-points. The metal reinforce should be embedded in theupper and also in the lower chord, and the reinforce in the lower chordshould preferably be embedded, at least in part, in the arch between thetwo chords. Preferably, also, the intermediate port-ions of thereinforces in the up' per and lower chords are tied to each other bysuitable metal ties. force in the lower chord may be provided withvertical side portions, stiening the beam and preferably connecting theedges of the upper and lower reinforces.

Referring to the drawings, the beam shown in Figs. l, 2, and 3 comprisesa lower chord A, au upper chord B, and an arch O, the ends of the lattersupported on and, in fact, formed in one with the ends of the lowerchord A and the central portion of the arch being, in fact, inV one withthe central portion of the upper chord B. The ends of the upper chord Bare supported upon the ends of the lower chord A 'by means ofsubstantially vertical end members D. The whole structure thereforeforms, in effect, a sort of trussed girder,

upon the upper portion of which the loads are received directly and thelower chord of which isstrained .in tension. The lower chord A being intension, as stated, is provided with an embedded metal reinforce,

Also the metal reinf preferably, as shown, in the form of asteeldiameter of the wire the latter will break before it can be pulledout of the concrete, so great is the adhesion. The downward and yendwise strains which are transmitted from the upper chord through thearch C are best transmitted to the lower chord by turning up the ends ofthe fabric E of the lower chord, as indicated at H, into the ends of thearch. They may extend throughout the length of the arch and should be,at least in part, in the arch, as shown. By this construction the beamtakes up within itself all endwise thrust,`so that the stress on thesupports K is directly vertical. Preferably, also, the u pper chord B isprovided with an embedded reinforce, such as the wire fabric L, thecenface of the concrete to take the tensile strains coming therein. Thisreinforce greatly relieves the haunches of the arch C, which accordingtoknown laws would have a tendency to rise under eccentric or very heavyconcentrated loads. The fabric of interlaced and bound wires distributesa great part of such strains throughout the upper chord, so as to lessenthe effect of the eccentricity or concentration of the load. In orderthat the lower chord A may be made very light, I preferably employ also'one or more ties M, attached to the upper and lower reinforces L and Eat intermediate points of the beam, so as to sustain and relieve theintermedi-ate portion of the lower chord A of its own weight and utilnize it purely for resisting the tensile strains y' exerted at itsopposite ends. The ties M are f preferably strips of heavy wire, asshown,

5o bent at their ends over the fabrics L and E.

The relative proportions of the several parts ofthe beam may beconsiderably varied from Athose shown, depending upon the permissibledepth of the beam and the magnitude and manner of distribution of theloads to be carried. The triangular panel between the end posts D, theupper chord B, and the haunches of the arch C may be filled in withconcrete without sacrificing any of the advantages of the inventionexcept that of lightness, or this panel and the panel between the archand the lower chord may contain a longitudinal web, such as is indicatedin dotted lines at N, Fig. 2, leaving a transverse opening at each sideof the beam, but not extending entirely therethrough. Instead of asingle arch C extending between two end posts tral portion of whichextends near the lower D a number of such arches may be used,constituting the structure, in eect, a latticed girder, and, as will beobvious to those skilled in the art, the same arch eect will be obtainedwhether its contour consists of curves or straight lines. The beam maybe made of such length asv to extend only between two adjacent supportsK, as indicated in Fig. 9, or it may be a continuous beam-that is,extending without break over more than two supports, as indicated inFig. l-in which case each span contains the several elements referredto, and the end posts D, and preferably the upper reinforce L ofadjacent spans, are integral with each other. In such a continuous beamthe upper chord is strained in tension at points above the supports, andtherefore a reinforce L' should extend continuously over the end post,which reinforce may be part of the fabric L and which is preferably inthe upper part of the concrete where the tensile strain is greatest.

The process of building the beam described will be understood from Fig.3. A suitable base or center O is provided, and upon this is molded thelower portion of the beam, (in the structure illustrated the lower chordA.) Upon this lower portion is then constructed a center P of anysuitable material, preferably of loose granular material, which can bereadily molded to the desired shape and readily Withdrawn, temporarysides Q being provided to determine the lateral edges of the beam andthe center P being built substantially out to these temporary sides. Onthe center P the upper portion of the beam is then molded, such upperportion at itsends extending down to the lower portion of thebealn,sothatwhen the concret'ehassufciently set it is supported upon thelower portion of the beam. After the concrete has set, the sides Q ofthe mold are'withdrawn, and the center .P is withdrawn laterally, so asto leave a transverseopening between the upper and lower portion, whichtransverse opening may extend entirely through, as indicated in Fig. 3,or may extend from each edge toward the center, as indicated in dottedlinesin Fig. 2. For building a beam constructed exactly as shown in theseveral longitudinalv sections illustrated the center P is made insuitable formto support an arch C, and after this arch is built-say inthe form shown in Fig. l-the process isextended by the building of asimilar center on the haunches of the arch to form the triangular panelsshown, and about this center are built the upper chord B and the endposts D. The metal reinforces described may be embedded in the concreteduring the laying of the same in the manner well known to thoseskilledinthe art. The packing and shaping of the centers of loosematerial may be very quickly accomplished, so that the arch ends mayjointhe ends of the lower chord and the arch center may join the center ofthe upper chord and the end posts be connected to the adjacentvmembersbefore ICC there has been any substantial setting of the concrete, so asto form a substantially integral structure. Where a number of spans areto be constructed in one, so as to form a continuous beam, the'sameprocess may be obviously applied with facility, requiring only amultiplication of the number of centers to be constructed without anyincrease in the time necessary to construct them or for the laying orsetting of the concrete. Since the centers are withdrawn throughopenings of their own full size, it is obvious that any style ofcentering may be employed, though for the reasons stated I prefer theloose granular material shown.

My invention provides also for stilfening concrete beams havingseparated upper and lower portions by means of a metallicstiifening-reinforce lying in a vertical plane and extendinglongitudinally of the beam and embedded at its upper and lower edges insaid upper and lower portions. This improvement is applicable withadvantage to any such beam regardless of the particular shape of theupper and lower portions. For example, they may be the horizontal chordsabove described or they may be one such chord and an arch, or the beammay comprise the several elements in the specic structure illustrated.Such a metallic stieniug-reinforce serves substantially the same purposeas the concrete web N, Fig. 2, and may be used with or without thisweb-as, for example, by being embedded therein-or it may extend across atransverse opening extending into or through the beam. A structureembodying this feature is shown in Figs. 4 to 7. The concrete in thiscase is substantially identical with that shown in Fig. 1, comprising alower plate A, ari-upper plate B, an arch C, and end posts D, arrangedabove any suitable supports K. In the lower and upper chords A and B areembedded fabrics E and L, similar to those in Fig. 1 and similarlyarranged. In order to provide the metallic stiiening described, thefabric E may be bent up to form vertical side portions R, preferablybound at their upper edges to the fabric L of the upper chord. The endsof the fabric E may be bent up into the end posts D, as indicated at S,and connected to the upper fabric, or they may be bent up into the lowerends of the arch, as indicated at H, Fig. 1. The ties M may be omittedwhere the vertical fabric is used, leaving the fabric to support thelower chord throughout its length; but I prefer to assist it with theties. The modifications in form and proportions referred to inconnection with the structure shown in Fig. 1 are also obviouslyapplicable to the structure with metallic stienin greinforce, and, infact,

to all the several structures shown. In buildthe opening a variation ofthe process illustrated iu Fig. 3 maybe utilized. Referringto Fig. 6,the center or mold-base O. and mold sides Q are identical with thoseshown in Fig. 3. As in the process described in connection with Fig. 3the lower portion of the beam is molded, the vertical reinforce R beingheld in position, the center of loose granular material P is constructedof the desired contour, and the upper portion of the beam is then moldedon this center. After giving the concrete suflicient time to set, theloose material P of the Y center may be withdrawn through theinterstices of they reinforce R. As in the former case the lower portionofthe beam may be the lower chord A and theupper portion may be anarched or a dat portion extending at its ends down to the lower chord,preferably both the arched portion C and the horizontal upper chord Bbeing formed one after the other, as described.

Where my improved beam is to be used in exposed situations,thetransverse openings at the sides may be closed-as, for example, byplastering-to give a better finish to the structure. With the verticalstiffening fabric described the mouth of the transverse opening at theside of the beam may be very conveniently covered in the mannerillustrated in Fig. 7. In this construction lathing, such as thetine-mesh Wire fabric T, may be attached to the stiffening fabric R anda suitable layer of plaster or cement U applied thereto and also to theedges of the solid portions of the beam, as shown, in order to finish itnicely. This layer of plaster or cement may be made such as to reinforcethe metallic stiening, and thus add to the strength of the beam.

Figs. 8 and 9 illustrate an embodiment of the invention very similar tothat shown in Fig. 1. These and the following figures illustrate asimple beamthat is to say, a beam long enough to extend over only asingle span between two supports K-as distinguished from the continuousbeam of Fig. 1 I of more than one span in length; In such asimple beamit is preferable that the end posts D should converge upwardly, asindicated.

The lower chord A, upper chord B, and archv C are substantiallyidenticalwith thec same parts shown in Fig. 1, as are also thereinforcing fabrics E and L. In addition to the ties M, which take thetensile strains due to the weight of the lower chord, I propose toemploy intermediate vertical members or posts V, preferably of concreteand surrounding the ties M. These posts are adapted to resistcompressive strains and serve, therefore, for transmitting the downwardstrains which come on the upper part of the beam to the lowerchord,where they are converted into tensile strains.

An embodiment of the invention including the features of Figs. 8 and 9,in connection with the vertical metallic reinforce of Fig. 4, isillustrated in Figs. 10 and 11. The concrete structure in these figuresis identical with that shown in Figs. 8 and 9. The embedded metallicfabric, however, is bent up IIO along each side, as indicated at R, toincrease the stiness of the structure, Fig. 10 being a section along theline 10 10 of Fig. 5. The panels or transverse openings in these casesmay be obtained by the processes indicated in Figs. 3 and 6, the onlymodification being in the number and shape of the centers of granularmaterial to be employed.

' The closing of the mouths of the transvers openings at the side edgesof the beams and the modifications in the relative arrangement andproportion of the elements of the beam referred to in connection withFig. 1 are obviously equally applicable to the beams shown in Figs. 8 to11.

The various types described are well adapted for use Without the lowerchord, especially in situations in which other means areprovided fortaking up the side thrust at the ends of the spans. The continuous beamillustrated in Fig. 1 is a good example of such a situation. The spansat the opposite ends of the complete span shown would take up the endthrust of the central span if the lower chord A were omitted.

Though I have described with great particularity of detail certainembodiments of my invention, yet it is to be understood that theinvention is not limited to the specific embodiments disclosed. Variousmodifications of the same in detail and in the arrangement andcombination of the parts may be made by those skilled in the art withoutdepartu re from the invention.

What I claim isl. In a beam, in combination, a lower chord, an upperchord, and an arch between said chords, each of said parts being ofconcrete.

2. In a beam, in combination alower chord, an arch supported at its endson said lower chord, and vertical members intermediate the ends of saidarch for transmitting downward strains thereon to the lower chord, eachof said parts being of concrete.

3. In a beam, in combination, an arch, a horizontal upper chord abovevthe arch, and vertical members joining the ends of said arch and chord,each of said parts being of concrete.

4. In a beam, in combination, alower chord, an upper chord, an archbetween said chords, and vertical members joining the ends of saidchords, each'of said parts being. of concrete.

5. In a beam, in combination, alower chord,

an upper chord, an arch between said chords, each of said parts being ofconcrete, and a metal reinforce embedded in said lower chord.

6. In abeam, in combination, a lower chord,

an upper chord, an arch between said chords,

each of said parts being of concrete, and a metal reinforce embedded insaid lower chord and at least in part in saidv arch.

7. In a beam, in combination, an upper chord, an arch below said upperchord and adapted to transmit strains from the intermediate portion ofsaid-upper chord toward the ends of the beam, each of said parts beingof concrete, and a metal reinforce embedded in said upper chord todistribute the eccentric or concentrated loads. thereon and, thusrelieve the haunches. of the arch.

8. In a beam, in combination, a lower chord, an upper chord, an archbetween said chords, each of said parts being of concrete, and metalreinforces embedded in said upper and lower chords.

9. In abeam, in combination, a lower chord, an upper chord, an archbetween said chords, each of said parts being of concrete, a metalreinforce embedded in said upper chord, and a metal reinforce embeddedin said lower chord and at least in part in said arch.

10. In v-a beam, in combination, a lower chord, an upper chord, an archbetween them,

each of said parts being of concrete, metal reinforces embedded in saidupper and lower chords, and a tie attached to said metal rein forces toconnect them to each other..

l1. In a beam, in combination, a lower chord, an upper chord, an archbetween said chords, each of said parts being of concrete, a metalreinforce embedded in said upper chord, a metal reinforce embedded insaid lower chord and at least in part in said arch, and a tie attachedto intermediate portions of said met-al reinforces to connect them toeach other.

12. A concrete beam having a transverse opening therein and a stiffeningmetallic reinforce in a vertical plane extending across said opening andembedded at its edges in the concrete.

13. In a beam, in combination, upper and lower portions of concreteseparated from each other, and a metallic stiffening-reinforce in avertical plane extending longitudinally of said beam and embedded at itsupper and lower edges in said upper and lower portions respectively.

14. In a beam, in combination, a horizon- IOO IIO

tal chord and an arch separated from each other at portions of theirlength, each of said parts being of concrete, and a metallicstiffening-reinforce in a vertical plane extending longitudinally insaid beam and embedded at its opposite edges in said chord and arch re-`ing horizontal portions embedded in saidA beam above and below saidopening, and vertical side portions joining the edges of said horizontalportions.

17.` A concrete beam having a transverse opening therein, and a layer ofplastic material extending over the mouth of said opening. 18. Alcontinuous beam comprising in combination a plurality of spans each ofwhich is limited by end posts of concrete and cornprises an upper' and alower portion of concrete having a transverse opening between them.

19. A continuous beam comprising a plurality of spans limited by endposts of concrete and having upper and lower portions of concrete havinga transverse opening between them, and a metallic reinforce extendingover the end post of two adjoining spans.

20. The process of building a concrete beam with a transverse openingtherein, which consists in molding a lower portion of the beam,constructing on said lower portion a suitable center extending to thelateral edges of the beam, molding on said center an upper portion ofthe beam supported at its ends on the lower portion, and, after theconcrete has set suciently, withdrawing the center laterally so as toleave a transverse opening in the beam.

2l. The process of building a concrete beam having a transverse openingtherein and an apertured vertical metallic reinforce extending acrosssaid opening, which consists in moldinga lower portion of the beam,arranging the reinforce in position, constructing on said lower portiona center of loose granular material, molding on said center an upperportion of the beam supported at its ends on the lower portion, and,after the concrete has set sufficiently, vwithdrawing said loosematerial through the vinterstices of said reinforce.

In witness whereof I have hereunto signed my name in the presence of twosubscribing witnesses.

WILLIAM N. WIGHT.

